1. Field of the Invention
The subject invention generally relates to a flexible polyurethane foam and a method of producing the flexible polyurethane foam. More specifically, the subject invention relates to flexible polyurethane foam that exhibits flame retardance.
2. Description of the Related Art
Polyurethane foams exhibit a wide range of stiffness, hardness, and density. One type of polyurethane foam, flexible polyurethane foam, is especially useful for providing cushioning, support, and comfort for furniture articles. For example, flexible polyurethane foam is often incorporated into furniture comfort articles, such as cushions, padding, mattresses, topper pads, and pillows, as well as furniture support articles, such as sofas, love seats, and chairs.
Flexible polyurethane foams are typically flammable, especially when subjected to repeated compression and bending, but can be formulated to resist small open flame ignition sources. The repeated compression and bending often results in compromise of the cellular structure of flexible polyurethane foams, generally referred to as flex fatigue. Since flexible polyurethane foams are repeatedly subjected to compression and bending and thus, over time, experience flex fatigue when used in furniture comfort and support articles, United States federal and state regulations currently proscribe flammability limits for flexible polyurethane foams. One such state regulation, California Technical Bulletin 117, specifies requirements, test procedures, and equipment for testing flame retardance of resilient filling materials, e.g. flexible polyurethane foams, in upholstered furniture.
Various approaches for producing flexible polyurethane foams exhibiting flame retardance and flexibility are known in the art. For example, many existing flexible polyurethane foams exhibiting flame retardance are produced via a reaction between toluene diisocyanate (TDI) and an isocyanate-reactive component that includes one or more polyols. TDI is generally utilized over other isocyanates because TDI is known to impart polyurethane foams with desirable physical and flex fatigue properties at low densities.
More common approaches for producing flexible polyurethane foams exhibiting flame retardance rely on inclusion of supplemental flame retardant additives in the isocyanate-reactive component. For example, flame retardant additives including minerals, such as aluminum trihydrate; salts, such as hydroxymethyl phosphonium salts; phosphorous compounds; phosphated esters; and halocarbons or other halogenated compounds, such as those containing bromine and/or chlorine; may be included in the isocyanate-reactive component.